Crown Graphic Special Top Rangefinder ??

[n2mf]

First question: Would any Crown Graphic Top Rangefinder Camera, that was known to have been calibrated to a Schneider Xenar 135mm/4.7 lens, be automatically calibrated to another Schneider Xenar 135mm/4.7 lens that wasn't original to the camera?

Second question: Are these Graflex top rangefinders easy to calibrate to other brands of 135mm lenses?

 

[n2mf]

Did some digging...I think I found my answer...The Top Rangefinders have cams, so if I understand it right, I can use any 135mm focal length lens as long as it has the 135mm cam...Correct?

 

[Dan Fromm]

Sorry, the cams are lens-specific, not focal length-specific. This because actual focal lengths of lenses of the same make, model, and engraved focal length will vary.

Here's a Zeiss example. I once bought 9 AGI F135 cameras, each with a pair of 38/4.5 Biogons, and a pair of 38/4.5 Biogons that had been held as spares. The F135 is fixed focus. Each lens was marked with its measured focal length. Design focal length is 38.5 mm, actuals ranged from 38.2 to 38.8. Each lens had a shim that sat between it and the camera's main casting to collimate the lens to infinity. Each shim was marked with its lens' serial number and its thickness, to 0.01 mm. There were many different shims. I don't think Schneider's quality control was more stringent than Zeiss'.

 

[BradS]

The TRF Crown Graphics use a cam. The only adjustments you can make to the RF are to change the cam and move the infinity stops. The cam that came with a camera that was originally fitted with a 135mm Xenar will certainly work with any other 135mm Xenar of similar vintage. It might or might not work with another make of 135mm lens. So, in practice, if you replace the original 135mm Xenar with a modern 135mm Sironar-N for example, the rangefinder will be off at either near or far distances - or both.

 

[n2mf]

Sorry, the cams are lens-specific, not focal length-specific. This because actual focal lengths of lenses of the same make, model, and engraved focal length will vary.

Here's a Zeiss example. I once bought 9 AGI F135 cameras, each with a pair of 38/4.5 Biogons, and a pair of 38/4.5 Biogons that had been held as spares. The F135 is fixed focus. Each lens was marked with its measured focal length. Design focal length is 38.5 mm, actuals ranged from 38.2 to 38.8. Each lens had a shim that sat between it and the camera's main casting to collimate the lens to infinity. Each shim was marked with its lens' serial number and its thickness, to 0.01 mm. There were many different shims. I don't think Schneider's quality control was more stringent than Zeiss'.

Thank you...Very helpful.

 

[n2mf]

The TRF Crown Graphics use a cam. The only adjustments you can make to the RF are to change the cam and move the infinity stops. The cam that came with a camera that was originally fitted with a 135mm Xenar will certainly work with any other 135mm Xenar of similar vintage. It might or might not work with another make of 135mm lens. So, in practice, if you replace the original 135mm Xenar with a modern 135mm Sironar-N for example, the rangefinder will be off at either near or far distances - or both.

I was going to try a Nikkor-W 135mm on the camera. So if I leave the current cam in, I may have to adjust the infinity stops? Or is there more to it than that?

 

[shutterfinger]

The TRF Crown Graphics use a cam. The only adjustments you can make to the RF are to change the cam and move the infinity stops. The cam that came with a camera that was originally fitted with a 135mm Xenar will certainly work with any other 135mm Xenar of similar vintage. It might or might not work with another make of 135mm lens. So, in practice, if you replace the original 135mm Xenar with a modern 135mm Sironar-N for example, the rangefinder will be off at either near or far distances - or both.

As Dan said, lens vary in actual focal length from their marked focal length, all brands, all focal lengths.

The list of Pacemaker Graphic Rangefinder cams is http://www.graflex.org/speed-graphic/top-rangefinder-cams.html
P31-132
P5-133.5
P6-135
P7-136.4

The Graphic Rangefinder, found on Pacemaker Graphic cameras from 1955 onward, is calibrated to read infinity when the cam follower arm is .437 ± .001 inch from the cam base. This is the only adjustment of this rangefinder.
See: http://www.southbristolviews.com/pics/Graphic/manual-pdf/TRFService.pdf . A lens that is focused at infinity on the ground glass with the RF indicating infinity will be in focus at infinity but be out of focus at closer than infinity distances depending on the focal length difference between the lens and the focal length the cam was cut for. A 133mm lens used with a P31 cam will be off from the 15-25 feet range and closer and when used with a P5 cam it will be off at about 10 feet and closer.

 

[n2mf]

As Dan said, lens vary in actual focal length from their marked focal length, all brands, all focal lengths.

The list of Pacemaker Graphic Rangefinder cams is http://www.graflex.org/speed-graphic/top-rangefinder-cams.html
P31-132
P5-133.5
P6-135
P7-136.4

The Graphic Rangefinder, found on Pacemaker Graphic cameras from 1955 onward, is calibrated to read infinity when the cam follower arm is .437 ± .001 inch from the cam base. This is the only adjustment of this rangefinder.
See: http://www.southbristolviews.com/pics/Graphic/manual-pdf/TRFService.pdf . A lens that is focused at infinity on the ground glass with the RF indicating infinity will be in focus at infinity but be out of focus at closer than infinity distances depending on the focal length difference between the lens and the focal length the cam was cut for. A 133mm lens used with a P31 cam will be off from the 15-25 feet range and closer and when used with a P5 cam it will be off at about 10 feet and closer.

Ok. Let me catch up...I have a Xenar 135mm lens, and I have a Top rangefinder Crown Graphic...They didn't start out in life together, but the camera did originally have another Xenar 135 with the right cam...If I marry these two together...No problem, right? But the Nikkor will not work with the rangefinder.

 

[Dan Fromm]

I have a Xenar 135mm lens, and I have a Top rangefinder Crown Graphic...They didn't start out in life together, but the camera did originally have another Xenar 135 with the right cam...If I marry these two together...No problem, right? But the Nikkor will not work with the rangefinder.

There's no guarantee that one 135/4.7 Xenar will have the same focal length as another. If the focal lengths differ the two lenses will need different RF cams and the bed stops will have to be positioned appropriately for the lens on the camera.

There's no guarantee that a randomly selected 135/5.6 Nikkor will have the same focal length as a randomly selected 135/4.7 Xenar. Same as above.

And there's no guarantee that a randomly selected 135 Nikkor with the same focal length as a randomly selected 135 Xenar will have the same flange-focal distance. If the focal lengths are identical the RF cam will be right for both lenses but the flange-focal distances aren't then the bed stops will have to positioned appropriately for the lens on the camera.

I'm sorry not to have given you the answer you want.

 

[shutterfinger]

Take your Pacemaker, Crown or Speed Graphic, Install the cam in the rangefinder, and pull the front standard out to the infinity stops and lock. Focus the rangefinder on an infinity target at least 5000 feet away. Lock the rails with the focus lock lever. Install one of the lens you have and check the focus on the ground glass.
A. If the ground glass image is in focus, aperture wide open, then focus on closer objects with the rangefinder and check the focus on the ground glass. If the ground glass agrees with the rangefinder then the lens and cam match.
B. If the focus is off then fold the infinity stops down and reposition the front standard to where infinity is in focus and lock the front standard. A shorter focal length than the infinity stops setting will focus behind the existing infinity stops while a longer than the infinity stop setting will focus infinity further out on the bed.

With both the rangefinder and ground glass in focus focus on objects closer and note where the lens and rangefinder diverge.
Standard focusing distance markings are Infinity, 100 ft., 50 ft., 25 ft., 15 ft., 10ft., 8 ft., 7 ft., 6 ft.

You currently have the camera, cam and lens in question.
Only you can answer the question of whether your lens match the cam closely enough to use.
You have been told how to find out.

 

[n2mf]

There's no guarantee that one 135/4.7 Xenar will have the same focal length as another. If the focal lengths differ the two lenses will need different RF cams and the bed stops will have to be positioned appropriately for the lens on the camera.

There's no guarantee that a randomly selected 135/5.6 Nikkor will have the same focal length as a randomly selected 135/4.7 Xenar. Same as above.

And there's no guarantee that a randomly selected 135 Nikkor with the same focal length as a randomly selected 135 Xenar will have the same flange-focal distance. If the focal lengths are identical the RF cam will be right for both lenses but the flange-focal distances aren't then the bed stops will have to positioned appropriately for the lens on the camera.

I'm sorry not to have given you the answer you want.

Sorry. I was just trying to understand. Guess I'm a little slow. Thank you for your help.

 

[n2mf]

Take your Pacemaker, Crown or Speed Graphic, Install the cam in the rangefinder, and pull the front standard out to the infinity stops and lock. Focus the rangefinder on an infinity target at least 5000 feet away. Lock the rails with the focus lock lever. Install one of the lens you have and check the focus on the ground glass.
A. If the ground glass image is in focus, aperture wide open, then focus on closer objects with the rangefinder and check the focus on the ground glass. If the ground glass agrees with the rangefinder then the lens and cam match.
B. If the focus is off then fold the infinity stops down and reposition the front standard to where infinity is in focus and lock the front standard. A shorter focal length than the infinity stops setting will focus behind the existing infinity stops while a longer than the infinity stop setting will focus infinity further out on the bed.

With both the rangefinder and ground glass in focus focus on objects closer and note where the lens and rangefinder diverge.
Standard focusing distance markings are Infinity, 100 ft., 50 ft., 25 ft., 15 ft., 10ft., 8 ft., 7 ft., 6 ft.

You currently have the camera, cam and lens in question.
Only you can answer the question of whether your lens match the cam closely enough to use.
You have been told how to find out.

Sorry. I was just trying to understand. Guess I'm a little slow. Thank you for your help.

 

[Dan Fromm]

Ah, this nonsense is confusing, especially for photographers who come to Graphics from cameras that use lenses in focusing mounts. FWIW, all of my Graphics (various 2x3 Pacemakers) have Kalart RFs, which don't use cams. Setting up a Kalart for a lens takes me an unpleasant half hour or so. Shutterfinger has more practice, may be able to do it more rapidly. I don't use the Kalarts, usually shoot from tripod and always focus on the ground glass.

 

[shutterfinger]

Setting up a Kalart for a lens takes me an unpleasant half hour or so. Shutterfinger has more practice, may be able to do it more rapidly.

No it usually takes me 45 minutes to a few hours with 1 1/2 hours the most common. On rare occasions I get one than can be done in 1/2 hour.


If I had 100+ copies each of all 135mm lens made for press cameras and each of the related cams in pristine condition, made a test with each lens and cam combination, recorded those results then I could give a definitive answer to your question but there could be an exception or two. Testing 25 to 50 lens of the same marked focal length would give a probable to work results with the possibly of more exceptions.

 

[BradS]

If I had 100+ copies each of all 135mm lens made for press cameras and each of the related cams in pristine condition, made a test with each lens and cam combination, recorded those results then I could give a definitive answer to your question but there could be an exception or two. Testing 25 to 50 lens of the same marked focal length would give a probable to work results with the possibly of more exceptions.

What a great experiment. Would be very interesting I think....but perhaps difficult at this point to even round up qnty 100 of the 135mm Xenar or even the 135mm Optar....not to mention the cost....cost is probably doable.

I guess I assume that mfgr's did this sort of thing back when the TRF Crowns were current / popular. Do you know if they did or not?

 

[shutterfinger]

I guess I assume that mfgr's did this sort of thing back when the TRF Crowns were current / popular. Do you know if they did or not?

Camera companies such as Graflex and Linhof use(d) a optical collimator to determine any given lens actual focal length and focusing curve. Lens manufacturers most likely use similar equipment to test each element and final assembly of each lens.

Linhof measured each lens and cut a cam for that lens then stamped that cam with the lens serial number.

Graflex measured the lens then chose the production cam that was closest to the measured focal length or cut a new cam only if there were no matching production cam. What they considered close is unknown to me. Looking at their cam list for their cameras it appears to be .5 to .7 millimeters as some cams are 1.4 mm apart.

Depending on the production era and the companies tolerance on each element as well as the assembled lens, a finished lens tolerance of 1% of the marked focal length when applied to a 135mm lens gives 133.65 mm to 136.35. The cam list suggest a tolerance range of -2% to +1%.

 

[Whiteymorange]

To be the Devil's advocate: Certainly there are differences in real, as opposed to labeled, focal lengths on any two lenses, no matter who made them. Copy camera lenses often have an actual focal length, determined by bench testing that particular lens, written somewhere on the lens barrel or flange by the technician. The ones I have rarely differ from the nominal focal length by more than a few tenths of a mm.

That said, I find it hard to imagine a case where, when using a range finder on a press camera, the difference between two lenses–of the same nominal focal length, from the same manufacturer–would vary more than what would be covered by the depth of field of that lens. In critical situations, using a lens with a vary short depth of field at its very widest aperture, this might become an issue. I would hazard a guess that these critical situations seldom involve using the range finder on a press camera. These cameras were made to be used in the field, by people who needed the first shot to be the money shot. The range finder on a camera like the Crwon is a "good enough" tool. Anything more exacting really calls for ground glass focusing.

Just saying

 

[BradS]

I have a TRF Crown Graphic with 135mm Optar lens. The range finder on this specimen is bloody accurate between 6 and 15 feet.

 

[Dan Fromm]

To be the Devil's advocate: Certainly there are differences in real, as opposed to labeled, focal lengths on any two lenses, no matter who made them. Copy camera lenses often have an actual focal length, determined by bench testing that particular lens, written somewhere on the lens barrel or flange by the technician. The ones I have rarely differ from the nominal focal length by more than a few tenths of a mm.

That said, I find it hard to imagine a case where, when using a range finder on a press camera, the difference between two lenses–of the same nominal focal length, from the same manufacturer–would vary more than what would be covered by the depth of field of that lens. In critical situations, using a lens with a vary short depth of field at its very widest aperture, this might become an issue. I would hazard a guess that these critical situations seldom involve using the range finder on a press camera. These cameras were made to be used in the field, by people who needed the first shot to be the money shot. The range finder on a camera like the Crwon is a "good enough" tool. Anything more exacting really calls for ground glass focusing.

Just saying

Whitey, my twenty little Biogons were taken from aerial cameras that were used at altitudes of no less than 600 feet. For a 38 mm lens, that's infinity. The air forces who bought the cameras didn't think that DoF would save them. That's why AGI, who made the cameras and fitted the lenses to them, went to the trouble of measuring the lenses' actual focal lengths and cutting shims (thickness specified to .01 mm) to collimate them.

The range finders fitted to Graphics are, when well-adjusted, very precise. They give no reason to settle for "good enough" because they can do better than that. If your press cameras' rangefinders aren't bang on and you use them, shame on you. If I wasn't clear, my little press cameras' rangefinders aren't bang on but I don't use them.

 

[fotch]

I have several Crown & Speed Graphics, all close to new condition, and any shots with the RF have always been perfect. I seldom us one with ground glass focusing because if that is what I needed, would use a view camera instead.

However, due to age, numerous owners, unknown condition, it would be a good idea to test your camera as several members suggested.

Personally, I love these cameras and their images, the large negatives, the versatility, the ruggedness, one of the great cameras of all time. JMHO